// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/base/hash_value.h"

#include <stdlib.h>

#include "base/base64.h"
#include "base/logging.h"
#include "base/sha1.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "crypto/sha2.h"

namespace net {

namespace {

    // CompareSHA1Hashes is a helper function for using bsearch() with an array of
    // SHA1 hashes.
    int CompareSHA1Hashes(const void* a, const void* b)
    {
        return memcmp(a, b, base::kSHA1Length);
    }

} // namespace

HashValue::HashValue(const SHA1HashValue& hash)
    : HashValue(HASH_VALUE_SHA1)
{
    fingerprint.sha1 = hash;
}

HashValue::HashValue(const SHA256HashValue& hash)
    : HashValue(HASH_VALUE_SHA256)
{
    fingerprint.sha256 = hash;
}

bool HashValue::FromString(const base::StringPiece value)
{
    base::StringPiece base64_str;
    if (value.starts_with("sha1/")) {
        tag = HASH_VALUE_SHA1;
        base64_str = value.substr(5);
    } else if (value.starts_with("sha256/")) {
        tag = HASH_VALUE_SHA256;
        base64_str = value.substr(7);
    } else {
        return false;
    }

    std::string decoded;
    if (!base::Base64Decode(base64_str, &decoded) || decoded.size() != size())
        return false;

    memcpy(data(), decoded.data(), size());
    return true;
}

std::string HashValue::ToString() const
{
    std::string base64_str;
    base::Base64Encode(base::StringPiece(reinterpret_cast<const char*>(data()),
                           size()),
        &base64_str);
    switch (tag) {
    case HASH_VALUE_SHA1:
        return std::string("sha1/") + base64_str;
    case HASH_VALUE_SHA256:
        return std::string("sha256/") + base64_str;
    default:
        NOTREACHED() << "Unknown HashValueTag " << tag;
        return std::string("unknown/" + base64_str);
    }
}

size_t HashValue::size() const
{
    switch (tag) {
    case HASH_VALUE_SHA1:
        return sizeof(fingerprint.sha1.data);
    case HASH_VALUE_SHA256:
        return sizeof(fingerprint.sha256.data);
    default:
        NOTREACHED() << "Unknown HashValueTag " << tag;
        // While an invalid tag should not happen, return a non-zero length
        // to avoid compiler warnings when the result of size() is
        // used with functions like memset.
        return sizeof(fingerprint.sha1.data);
    }
}

unsigned char* HashValue::data()
{
    return const_cast<unsigned char*>(const_cast<const HashValue*>(this)->data());
}

const unsigned char* HashValue::data() const
{
    switch (tag) {
    case HASH_VALUE_SHA1:
        return fingerprint.sha1.data;
    case HASH_VALUE_SHA256:
        return fingerprint.sha256.data;
    default:
        NOTREACHED() << "Unknown HashValueTag " << tag;
        return NULL;
    }
}

bool IsSHA256HashInSortedArray(const SHA256HashValue& hash,
    const uint8_t* array,
    size_t array_byte_len)
{
    DCHECK_EQ(0u, array_byte_len % crypto::kSHA256Length);
    const size_t arraylen = array_byte_len / crypto::kSHA256Length;
    return NULL != bsearch(hash.data, array, arraylen, crypto::kSHA256Length, CompareSHA1Hashes);
}

} // namespace net
